Variability in the Functional Domains of the Rho-Modifying Toxins of Yersinia pseudotuberculosis

Abstract

Pathogenesis of the disease caused by Yersinia pseudotuberculosis is associated with the production of a set of toxins. The plasmid-encoded YopE toxin and the chromosome-encoded cytotoxic necrotizing factor (CNF) modify the activity of small GTPases of the Rho family, inducing multiple changes in the target host cell. The variability in the YopE and CNF domains involved in protein–protein interactions with small Rho GTPases was studied in 33 strains isolated from patients clinically diagnosed with Far East scarlet-like fever (FESLF) and from environmental sources in Russia. All FESLF-associated strains and the majority of environmental strains carried the same yopE allele. The allele differed from alleles described in European isolates by a single nonsynonymous substitution. A distinct allele with two nonsynonymous substitutions was found in a single environmental strain. All but one strain had a deletion in the cnf gene. The deletion caused a total loss of the Rho-binding domain of CNF. Our results demonstrate that the yopE gene is highly conserved and suggest that CNF toxin is not involved in the regulation of GTPase activity in Y. pseudotuberculosis strains isolated in Russia.